Understanding how the solar cycle paces space weather risk
The solar cycle of activity modulates the occurrence of extreme space weather events at earth, so that the sunspot number (SSN) is a parameter for the overall intensity of space weather. Extreme space weather events can affect critical infrastructure on earth such as communications, satellites and power grids. Space weather also modulates the overall state of the ionosphere which affects communications and satellite operation in low earth orbit. Well-established statistical tools can give quantitative estimates of the occurrence likelihood of space weather events where there are high quality ground based magnetometer data and indices, that is, over the last few solar cycles. GPS data now spans more than one solar cycle, so that we can begin to discern the detailed relationship between SSN and the overall state of the ionosphere. However, no two solar cycles are of the same duration or activity level. To quantify how SSN translates to space weather risk requires analysis extending back over multiple cycles using observations that are available going back over 150 years, such as the aa index, sunspot records and anecdotal reports of aurorae available over several-100 years. These data are not well-sampled time-series but nevertheless carry information on extreme event occurrence and magnitude. Taken together, these observations can quantify the solar cycle variation of space weather risk and provide new insights into the underlying mechanisms pacing the solar cycle of activity.
S. C. Chapman, T. Dudok de Wit, A solar cycle clock for extreme space weather. Sci Rep 14, 8249 (2024). doi:10.1038/s41598-024-58960-5
Sandra Chapman is primarily but not exclusively a plasma physicist working on non-linear and complex systems in astrophysics and in the laboratory. She is Professor of Physics and Director of the Centre for Fusion, Space and Astrophysics at the University of Warwick. Recognition for her work includes the AGU Fall Meeting Ed Lorenz Lecture, the RAS Chapman Medal and the EGU Johannes Alfvén Medal.
Sandra was a Fulbright Scholar, a Fellow at the Radcliffe Institute for Advanced Study Harvard, an ISSI Geiss Fellow and has also been granted Research Fellowships by the Nuffield Foundation and the Japan Society for the Promotion of Science. She has published over 200 papers in the refereed literature and a textbook on Electrodynamics. She is also an artist who works to bridge the ‘arts- science divide’ and has held a NESTA Dreamtime fellowship – working as an artist with the British Antarctic Survey in Antarctica.